Osteoporosis

Please note that this section contains my personal notes from my readings on this topic.

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“Americans consume more cow’s milk and its products per person than most populations in the world. So Americans should have wonderfully strong bones, right? Unfortunately not. A recent study showed that American women aged fifty and older have one of the highest rates of hip fractures in the world. The only countries with higher rates are in Europe and in the south Pacific (Australia and New Zealand) where they consume even more milk than the United States.”

“An excess rate of hip fractures is often used as a reliable indicator of osteoporosis, a bone disease that especially affects women after menopause. It is often claimed to be due to an inadequate intake of calcium. Therefore, health policy people often recommend higher calcium consumption. Dairy products are particularly rich in calcium, so the dairy industry eagerly supports efforts to boost calcium consumption. These efforts have something to do with why you were told to drink your milk for strong bones – the politics of which are discussed in Part IV.

Something is amiss, though, because those countries that use the most cow’s milk and its products also have the highest fracture rates and the worst bone health. One possible explanation is found in a report showing an impressively strong association between animal protein intake and bone fractures for women in different countries. Authored in 1992 by researchers at Yale University School of Medicine, the report summarized data on protein intake and fracture rates taken from thirty-four separate surveys in sixteen countries that were published in twenty-nine peer-reviewed research publications. All the subjects in these surveys were women fifty years and older. It found that a very impressive 70% of the fracture rate was attributable to the consumption of animal protein.

We have had evidence for well over a hundred years that animal protein decreases bone health.”

In The China Study, Dr. Campbell proceeds to explain studies that test how consumption of animal protein leads to increased bone fracture rates. He then writes:

“These studies are compelling for several reasons. They were published in leading research journals, the authors were careful in their analyses and interpretation of data, they included a large number of individual research reports, and the statistical significance of the association of animal protein with bone fracture rates is truly exceptional. They cannot be dismissed as just another couple of studies; the most recent study represents a summary of eighty-seven separate surveys!

The Study of Osteoporotic Fractures Research Group at the University of California at San Francisco published yet another study of over 1,000 women aged sixty-five and up. Like the multi-country study, researchers characterized women’s diets by the proportions of animal and plant protein. After seven years of observations, the women with the highest ratio of animal protein to plant protein had 3.7 times more bone fractures than the women with the lowest ratio. Also during this time the women with the high ratio lost bone almost four times as fast as the women with the lowest ratio.

Experimentally, this study is high quality because it compared protein consumption, bone loss and broken bones for the same subjects. This 3.7-fold effect is substantial, and is very important because the women with the lowest bone fracture rates still consumed, on average, about half of their total protein from animal sources. I can’t help but wonder how much greater the difference might have been had they consumed not 50% but 0-10% of their total protein from animal sources.

These observations raise a serious question about the widely advertised claim that protein-rich dairy foods protect our bones. And yet we still are warned almost daily about our need for dairy foods to provide calcium for strong bones. An avalanche of commentary warns that most of us are not meeting our calcium requirements, especially pregnant and lactating women. This calcium bonanza, however, is not justified. In one study of ten countries, a higher consumption of calcium was associated with a higher – not lower – risk of bone fracture (Chart 10.3 in the book). Much of the calcium intake shown in this chart, especially in high consumption countries, is due to dairyfoods, rather than calcium supplements or non-dairy food sources of calcium.

Mark Hegsted was a long-time Harvard professor. He worked on the calcium issue beginning in the early 1950s, was a principal architect of the nation’s first dietary guidelines in 1980 and in 1986 published this graph… Hegsted, backed by his exceptional experience in calcium research, said in his 1986 paper, “… hip fractures are more frequent in populations where dairyproducts are commonly consumed and calcium intakes are relatively high.”